A stirling type multi-material food 3D printing system and method

Abstract

The application discloses a Stirling type multi-material food 3D printing system and method, and belongs to the technical field of food 3D printing. The printing system comprises an outer cylinder fixedly arranged along a vertical direction, an inner cylinder coaxially arranged along an axial direction in the outer cylinder, a plurality of extrusion barrels uniformly arranged along the axial direction between the outer cylinder and the inner cylinder, and the bottom ends of the extrusion barrels being communicated with the inner cylinder. A main screw and an extrusion screw are respectively arranged along the axial direction in the inner cylinder and the extrusion barrel, the main screw is rotationally connected with the inner cylinder, the extrusion screw is rotationally connected with the extrusion barrel, a nozzle switching mechanism is arranged at the bottom end of the outer cylinder, a printing platform is arranged below the nozzle switching mechanism, a screw control mechanism is arranged at the top end of the outer cylinder, and the screw control mechanism is used for controlling the rotation of the corresponding extrusion screw. The application can use multiple materials in a single printing process by arranging the plurality of extrusion barrels, provides the possibility for creating a complex food structure with multiple levels or multiple colors, and achieves the purpose of simultaneously or independently extruding and precisely controlling the multiple materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food 3D printing, and in particular to a Stirling type multi-material food 3D printing system and method. BACKGROUND

[0002] In existing food 3D printing technology, the flexibility and efficiency of the equipment are often limited by various factors. First, although some systems support multi-material printing, independent control of different colors of the same material remains a challenge, and simultaneous or independent extrusion of multiple materials often cannot be accurately controlled, which affects the aesthetics and functionality of the product. Second, the nozzle selection and replacement mechanism of most existing devices is relatively primitive, usually only equipped with a limited number of nozzles, and the process of replacing the nozzle is inefficient, unable to quickly adapt to different printing needs, such as in application scenarios requiring the use of nozzles of different shapes or aperture. This limits the printing complexity and production speed. In addition, the temperature control of the nozzle in existing technology is often not precise enough, unable to effectively preheat or properly solidify the printed food, affecting the structural integrity and safety of the food. These technical limitations not only reduce the application potential of food 3D printing, but also increase the complexity and cost of the production process, hindering the widespread application and development of 3D printing technology in the food industry. Therefore, there is an urgent need for an improved system that can provide more flexible nozzle management, more accurate multi-material control, and more optimized temperature regulation functions to address these problems in existing technology. SUMMARY

[0003] The purpose of the present application is to provide a Stirling type multi-material food 3D printing system and method that can solve the problems of low nozzle switching efficiency, inaccurate multi-material printing control, slow nozzle preheating speed, and low food solidification efficiency in existing technology.

[0004] The present application adopts the following technical solution: a Stirling type multi-material food 3D printing system, comprising an outer cylinder fixedly arranged in the vertical direction, an inner cylinder coaxially arranged in the axial direction inside the outer cylinder, a plurality of extrusion barrels uniformly arranged in the axial direction between the outer cylinder and the inner cylinder, the bottom ends of the extrusion barrels being in communication with the inner cylinder; a main screw and an extrusion screw are respectively arranged in the axial direction inside the inner cylinder and the extrusion barrel, the main screw is rotationally connected with the inner cylinder, and the extrusion screw is rotationally connected with the extrusion barrel; a nozzle switching mechanism is arranged at the bottom end of the outer cylinder, a printing platform is arranged below the nozzle switching mechanism, and a screw control mechanism is arranged at the top end of the outer cylinder, the screw control mechanism being used to control the rotation of the corresponding extrusion screw.

[0005] Further, the screw control mechanism comprises a main shaft connected with the output shaft of the first motor and a plurality of driven shafts arranged along the axial direction around the main shaft, gears are fixedly arranged on the main shaft and the driven shafts in the same horizontal plane, a first cylinder corresponding to the driven shaft is fixedly arranged in the annular space between the main shaft and the driven shaft, and a switching gear is fixedly arranged on the output shaft of the first cylinder; the bottom end of the main shaft is fixedly arranged with the main screw, and the bottom end of the driven shaft is fixedly arranged with the extrusion screw; the first electromagnetic clutch is arranged between the main shaft and the output shaft of the first motor.

[0006] Further, the nozzle switching mechanism comprises a transmission shaft, a transmission disc, an inner clamping ring and an outer clamping ring, a second cylinder is arranged between the transmission shaft and the transmission disc, a top block is fixedly arranged on the output shaft of the second cylinder, the connection between the transmission shaft and the transmission disc is realized by driving the top block into the clamping groove arranged on the outer surface of the transmission shaft through the second cylinder, a plurality of third cylinders are arranged along the circumference between the transmission disc and the inner clamping ring, the fixed end of the third cylinder is fixedly arranged with the transmission disc, the output end of the third cylinder is fixedly arranged with the block inserted into the slot arranged on the outer surface of the inner clamping ring, thereby realizing the connection between the transmission disc and the inner clamping ring, annular sliding grooves are arranged on the inner clamping ring and the outer clamping ring, a plurality of fourth cylinders are arranged along the circumference through the annular sliding grooves, the output end of the fourth cylinder is close to the annular space formed between the inner clamping ring and the outer clamping ring, the output end of the fourth cylinder is fixedly arranged with the plug, a plurality of nozzles are uniformly arranged along the circumference in the annular space formed between the inner clamping ring and the outer clamping ring, the outer surface of each nozzle is arranged with the insertion slot, the output end of the fourth cylinder drives the plug to be inserted into the insertion slot arranged on the outer surface of the nozzle, thereby realizing the fixed connection between the inner clamping ring, the outer clamping ring and the nozzle.

[0007] Further, the nozzle switching mechanism comprises a transmission shaft, a transmission disc, an inner clamping ring and an outer clamping ring, a second cylinder is arranged between the transmission shaft and the transmission disc, a top block is fixedly arranged on the output shaft of the second cylinder, the connection between the transmission shaft and the transmission disc is realized by driving the top block into the clamping groove arranged on the outer surface of the transmission shaft through the second cylinder, a plurality of third cylinders are arranged along the circumference between the transmission disc and the inner clamping ring, the fixed end of the third cylinder is fixedly arranged with the transmission disc, the output end of the third cylinder is fixedly arranged with the block inserted into the slot arranged on the outer surface of the inner clamping ring, thereby realizing the connection between the transmission disc and the inner clamping ring, annular sliding grooves are arranged on the inner clamping ring and the outer clamping ring, a plurality of fourth cylinders are arranged along the circumference through the annular sliding grooves, the output end of the fourth cylinder is close to the annular space formed between the inner clamping ring and the outer clamping ring, the output end of the fourth cylinder is fixedly arranged with the plug, a plurality of nozzles are uniformly arranged along the circumference in the annular space formed between the inner clamping ring and the outer clamping ring, the outer surface of each nozzle is arranged with the insertion slot, the output end of the fourth cylinder drives the plug to be inserted into the insertion slot arranged on the outer surface of the nozzle, thereby realizing the fixed connection between the inner clamping ring, the outer clamping ring and the nozzle.

[0008] Further, the lifting mechanism comprises a threaded rod arranged along the vertical direction, the threaded rod is threadedly connected with the sliding block fixedly arranged on the first electric telescopic rod, the sliding block is arranged to slide along the vertical direction, and the output end of the first electric telescopic rod is fixedly arranged with the push block; the top end of the threaded rod is connected with the transmission shaft through the second electromagnetic clutch.

[0009] Further, the cooling mechanism is arranged below the printing platform, and the heating mechanism is arranged on the left side of the nozzle bank; the cooling mechanism and the heating mechanism both comprise heat exchange devices, working medium of the heat exchange devices is nitrogen, cooling medium of the heat exchange device of the cooling mechanism is cooling liquid, and heating medium of the heat exchange device of the heating mechanism is water; the hot end and the cold end of the Stirling piston system heat and cool the water and the cooling liquid respectively, so that the water obtains heat and returns to the heat exchange device of the heating mechanism to heat the nitrogen, thereby preheating and drying the nozzles in the nozzle bank and the nozzles in the inner clamping ring and the outer clamping ring, and the cold end and the hot end of the Stirling piston system heat and cool the water and the cooling liquid respectively, so that the temperature of the cooling liquid is reduced and returns to the heat exchange device of the cooling mechanism to cool the nitrogen, thereby cooling and solidifying the material printed above the printing platform.

[0010] Further, the Stirling piston system comprises a cylinder and a piston slidingly arranged in the cylinder in the left-right direction, a piston rod is fixedly arranged on the left side of the piston, a chamber on the left side of the piston in the cylinder is a hot end chamber, and a chamber on the right side of the piston in the cylinder is a cold end chamber; a communication pipe is arranged between the hot end chamber and the cold end chamber to communicate the hot end chamber and the cold end chamber, two heat exchangers are installed on the communication pipe, a regenerator is arranged between the two heat exchangers, a first heating medium outlet end of the left heat exchanger and a heating medium inlet end of the heat exchange device of the heating mechanism are communicated through a first hot water pipe, a heating medium return end of the left heat exchanger and a second heating medium outlet end of the heat exchange device of the heating mechanism are communicated through a second hot water pipe, a cooling medium first outlet end of the right heat exchanger and a cooling medium inlet end of the heat exchange device of the cooling mechanism are communicated through a first cold water pipe, and a cooling medium return end of the right heat exchanger and a cooling medium second outlet end of the heat exchange device of the cooling mechanism are communicated through a second cold water pipe.

[0011] Further, the left end of the piston rod is rotationally connected with a connecting rod, the left end of the connecting rod is rotationally connected with a crank pin, both ends of the crank pin are fixedly arranged with cranks in the radial direction, the ends away from the crank pin of the cranks are fixedly arranged with main rotating shafts, the main rotating shafts are rotationally connected with the fixed frame, and the upper main rotating shaft is connected with the output shaft of the second motor through a transmission mechanism.

[0012] Further, the lower main rotating shaft is connected with the transmission shaft through a speed reducer.

[0013] The use method of any one of the above Stirling type multi-material food 3D printing systems, characterized in that it comprises the following steps:

[0014] A: the first electromagnetic clutch is disconnected, and then the switching gear is pushed to move upward by the corresponding first cylinder, so that the main shaft and the corresponding driven shaft are engaged through the gear, then the first electromagnetic clutch is connected, so that the first motor drives the corresponding driven shaft to rotate through the main shaft, and then the corresponding extrusion screw is driven to rotate, so that the material in the set extrusion barrel enters the inner barrel, and the main screw in the inner barrel extrudes the material through the nozzle, and the food printing on the printing platform is completed;

[0015] B: the second motor drives the stirling piston system to operate, and the reducer operates at the same time, the stirling piston system exchanges heat with the working medium nitrogen of the heat exchange device through the cold temperature end heat exchanger and the hot temperature end heat exchanger respectively, so that the nitrogen of the heat exchange device of the heating mechanism obtains heat, and the nitrogen of the heat exchange device of the cooling mechanism is cooled, and then the hot nitrogen preheats the nozzle in the nozzle library and the nozzle between the inner clamping ring and the outer clamping ring, and the cold nitrogen cools and fixes the printed material above the printing platform;

[0016] C: when the nozzle needs to be replaced, the third electromagnetic clutch is closed or the third electromagnetic clutch is disconnected, the third electric telescopic rod drives the second bevel gear to move and engage with the two first bevel gears; so that the output shaft of the reducer drives the transmission shaft to rotate, the transmission shaft drives the inner clamping ring and the outer clamping ring to rotate, and then drives the nozzle between the inner clamping ring and the outer clamping ring to rotate, so that the nozzle to be replaced is rotated to the upper side of the inner barrel and is connected with the inner barrel, and the nozzle is replaced;

[0017] D: when the nozzle needs to be installed between the inner clamping ring and the outer clamping ring, the second electromagnetic clutch is closed, so that the transmission shaft drives the threaded rod to rotate, the threaded rod drives the first electric telescopic rod to move upward through the sliding block, so that the first electric telescopic rod moves to the set position, the second electromagnetic clutch is disconnected, and the first electric telescopic rod extends to the right to push the nozzle in the corresponding nozzle chamber to the mounting platform on the right side, at this time, the inner clamping ring and the outer clamping ring are rotated to the set position through the method of step C, so that the positions of the inner clamping ring and the outer clamping ring with empty space are located directly above the mounting platform, and then the second electric telescopic rod pushes the mounting platform upward, so that the mounting platform drives the nozzle to move upward, so that the nozzle enters between the inner clamping ring and the outer clamping ring and is fixed in the insertion slot of the nozzle through the insertion block of the fourth cylinder.

[0018] One, the present application can use multiple materials in a single printing process by setting a plurality of extrusion barrels, which provides the possibility for creating complex food structures with multiple levels or multiple colors, and achieves the purpose of precise control of simultaneous or independent extrusion of multiple materials.

[0019] Secondly, the present application can be equipped with multiple nozzles by setting the nozzle switching system, each of which is specially designed to optimize the printing of a specific type of food material; this nozzle compatibility allows the printer to handle any material from high to low viscosity, from fine detail printing to fast large-area filling, thereby greatly expanding the range of printable materials;

[0020] Thirdly, the present application allows quick replacement of different types of nozzles through the nozzle switching mechanism to meet a wider range of printing applications, improving the applicability and flexibility of the device; the independent control function of the extrusion device allows the extrusion of multiple materials individually or in combination, enhancing the diversity and innovation of printing jobs

[0021] Fourthly, the present application effectively controls the heating and cooling process by setting the hot end and cold end of the Stirling piston system, the hot end uses the efficient heat energy conversion of the Stirling piston to quickly transfer heat to the nozzle, achieving its rapid preheating, heat preservation and drying, thereby adapting to the printing needs of various materials. The cold end is responsible for quickly absorbing the heat of the printed area, accelerating the cooling and solidification of the food layer, ensuring the accuracy and stability of the printed food structure. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of the overall structure of the present application;

[0023] Figure 2 is a schematic diagram of the internal structure of the transmission shaft and transmission disc of the present application;

[0024] Figure 3 is a schematic diagram of the internal structure of the screw control mechanism of the present application;

[0025] Figure 4 is a schematic diagram of the internal structure of the outer cylinder of the present application;

[0026] Figure 5 is a schematic diagram of the top view structure of the inner clamping ring and the outer clamping ring of the present application;

[0027] Figure 6 、 7 and 8 are schematic diagrams of the structure of the nozzle with different sizes of outlet diameter of the present application;

[0028] Figure 9 、 10 and 11 are schematic diagrams of the structure of the nozzle with different outlet shapes of the present application.

[0029] 1, outer cylinder; 2, inner cylinder; 3, extrusion cylinder; 4, main screw; 5, extrusion screw; 6, nozzle switching mechanism; 7, screw control mechanism; 8, nozzle; 9, output shaft of first motor; 10, main shaft; 11, driven shaft; 12, gear; 13, first cylinder; 14, switching gear; 15, first electromagnetic clutch; 16, protective cover; 17, transmission shaft; 18, transmission disc; 19, inner clamping ring; 20, outer clamping ring; 21, second cylinder; 22, top block; 23, third cylinder; 24, block; 25, annular chute; 26, fourth cylinder; 27, plug; 28, slot; 29, partition; 30, nozzle library; 31, nozzle bin; 32, first electric telescopic rod; 33, mounting platform; 34, second electric telescopic rod; 35, threaded rod; 36, sliding block; 37, second electromagnetic clutch; 38, heat exchange device; 39, cylinder; 40, piston; 41, piston rod; 42, communication pipe; 43, heat exchanger; 44, regenerator; 45, first heating medium outlet end; 46, heating medium inlet end; 47, first hot water pipe; 48, heating medium return end; 49, second heating medium outlet end; 50, second hot water pipe; 51, cooling medium first outlet end; 52, cooling medium inlet end; 53, first cold water pipe communication; 54, cooling medium return end; 55, cooling medium second outlet end; 56, second cold water pipe; 57, spring; 58, connecting rod; 59, crank pin; 60, main rotating shaft; 61, fixed frame; 62, output shaft of second motor; 63, fourth electric telescopic rod; 64, output shaft of speed reducer; 65, third electromagnetic clutch; 66, third electric telescopic rod; 67, first bevel gear; 68, second bevel gear; 69, rotating platform; 70, displacement platform; 71, gas storage tank; 72, heating fin; 73, speed reducer; 74, push block; 75, nitrogen pipeline; 77, guide rail. DETAILED DESCRIPTION

[0030] Please refer to Figures 1-11 , the following detailed description of the present application is made in conjunction with the accompanying drawings and examples:

[0031] The Striling type multi-material food 3D printing system comprises an outer cylinder 1 fixedly arranged along the vertical direction, an inner cylinder 2 coaxially arranged along the axial direction in the outer cylinder 1, a plurality of extrusion barrels 3 arranged along the axial direction and uniformly distributed along the circumferential direction between the outer cylinder 1 and the inner cylinder 2, the bottom ends of the extrusion barrels 3 being in communication with the inner cylinder 2, a main screw 4 and an extrusion screw 5 being respectively arranged along the axial direction in the inner cylinder 2 and each extrusion barrel 3, the main screw 4 being rotationally connected with the inner cylinder 2, the extrusion screw 5 being rotationally connected with the extrusion barrel 3, a nozzle switching mechanism 6 being arranged at the bottom end of the outer cylinder 1, a printing platform being arranged below the nozzle switching mechanism 6, a screw control mechanism 7 being arranged at the top end of the outer cylinder 1, the screw control mechanism 7 being used for controlling the rotation of the corresponding extrusion screw 5, so that the material in the corresponding extrusion barrel 3 is extruded into the inner cylinder 2, the material in the inner cylinder 2 is extruded through a nozzle 8 by the main screw 4, and the food printing is completed.

[0032] In the embodiment, the screw control mechanism 7 comprises a main shaft 10 connected with the output shaft 9 of the first motor and a plurality of driven shafts 11 arranged along the axial direction and surrounding the main shaft 10 along the circumferential direction, gears 12 being fixedly arranged on the main shaft 10 and the driven shafts 11 in the same horizontal plane, a plurality of first air cylinders 13 corresponding to the driven shafts 11 being fixedly arranged in the annular space between the main shaft 10 and the driven shafts 11, and the output shafts of the first air cylinders 13 being fixedly arranged with switching gears 14; the bottom end of the main shaft 10 is fixedly arranged with the main screw 4, and the bottom end of the driven shaft 11 is fixedly arranged with the corresponding extrusion screw 5; a first electromagnetic clutch 15 is arranged between the main shaft 10 and the output shaft 9 of the first motor, when it is needed to switch the rotation of different driven shafts 11, the first electromagnetic clutch 15 is first disconnected, then the corresponding switching gear 14 is pushed upward by the corresponding first air cylinder 13 to make the switching gear 14 simultaneously mesh with the gears 12 on the main shaft 10 and the corresponding driven shaft 11, then the first electromagnetic clutch 15 is connected, so as to realize the purpose that the first motor drives the corresponding driven shaft 11 to rotate through the main shaft 10, and then realizes the purpose that the corresponding extrusion screw 5 is driven to rotate, so as to realize the purpose that the material in the set extrusion barrel 3 enters the inner cylinder 2, the material in the inner cylinder 2 is then extruded through the nozzle 8 by the main screw 4, and the food printing is completed; by controlling different first air cylinders 13 to push the switching gears 14 to move upward, the purpose that the materials in different extrusion barrels 3 are extruded into the inner cylinder 2 is realized, the combined printing of multiple materials is carried out, and independent control is realized.

[0033] In use, different materials are filled in different extrusion barrels 3, a printing substrate is placed on a printing platform, the first motor rotates to drive the main shaft 10 to rotate through the first electromagnetic clutch 15, when printing of a certain material is needed, the corresponding first air cylinder 13 is controlled to push the switching gear 14 to move upward, so that the main shaft 10 is engaged with the corresponding driven shaft 11 through the upwardly lifted switching gear 14, the corresponding driven shaft 11 rotates synchronously with the main shaft 10, and then drives the corresponding extrusion screw 5 to rotate, so that the material in the corresponding extrusion barrel 3 enters the inner barrel 2 from the bottom end, the main screw 4 in the inner barrel 2 extrudes the material through the nozzle 8, and the material is printed on the printing substrate placed on the printing platform, and the food printing is completed.

[0034] In order to protect the gear 12, the switching gear 14 and the first air cylinder 13, in the embodiment, the outer part of the screw control mechanism 7 is provided with a protective cover 16 fixedly arranged at the top end of the outer barrel 1, the gear 12, the switching gear 14, the first air cylinder 13 and the first electromagnetic clutch 15 are located in the protective cover 16, the fixed end of the first air cylinder 13 is fixedly arranged with the inner bottom wall of the protective cover 16, and the main shaft 10 is fixedly arranged with the main screw 4 by penetrating downwardly through the protective cover 16; by arranging the protective cover 16, the gear 12, the switching gear 14, the first air cylinder 13 and the first electromagnetic clutch 15 are effectively protected, the operation is more reliable, the service life is prolonged, and the appearance of the equipment is more beautiful.

[0035] In the embodiment, the nozzle switching mechanism 6 comprises a transmission shaft 17, a transmission disc 18, an inner clamping ring 19 and an outer clamping ring 20, a second air cylinder 21 is arranged horizontally between the transmission shaft 17 and the transmission disc 18, the fixed end of the second air cylinder 21 is fixedly arranged with the transmission disc 18, the output shaft of the second air cylinder 21 is fixedly arranged with a top block 22, the connection between the transmission shaft 17 and the transmission disc 18 is realized by means of the second air cylinder 21 to push the top block 22 into the clamping groove on the outer surface of the transmission shaft 17, a plurality of third air cylinders 23 are arranged horizontally along the circumference between the transmission disc 18 and the inner clamping ring 19, the fixed end of the third air cylinder 23 is fixedly arranged with the transmission disc 18, the output end of the third air cylinder 23 is fixedly arranged with a block 24 inserted into the block groove on the outer surface of the inner clamping ring 19, thereby realizing the connection between the transmission disc 18 and the inner clamping ring 19, the annular sliding grooves 25 are arranged on the inner clamping ring 19 and the outer clamping ring 20, the inner clamping ring 19 and the outer clamping ring 20 are correspondingly arranged with a plurality of fourth air cylinders 26 along the circumference through the annular sliding grooves 25, the output end of the fourth air cylinder 26 is close to the annular space formed between the inner clamping ring 19 and the outer clamping ring 20 for fixing the nozzle 8, the output end of the fourth air cylinder 26 is fixedly arranged with an insertion block 27, a plurality of nozzles 8 are uniformly arranged along the circumference in the annular space formed between the inner clamping ring 19 and the outer clamping ring 20, the outer surface of each nozzle 8 is arranged with an insertion groove 28, the output end of the fourth air cylinder 26 arranged on both sides of the nozzle 8 pushes the insertion block 27 to be inserted into the two insertion grooves 28 arranged on the circumference of the nozzle 8, thereby realizing the fixed connection between the inner clamping ring 19, the outer clamping ring 20 and the nozzle 8; in use, the rotation of the transmission shaft 17 drives the transmission disc 18 to rotate through the second air cylinder 21, the transmission disc 18 drives the inner clamping ring 19 to rotate through the third air cylinder 23, the inner clamping ring 19 and the outer clamping ring 20 drive the nozzle 8 to rotate through the fourth air cylinder 26, when the nozzle 8 rotates around the transmission shaft 17 and is located below the inner cylinder 2, the nozzle 8 is butt-jointed with the bottom end of the inner cylinder 2, so that the material of the inner cylinder 2 is extruded downward from the corresponding nozzle 8, thereby realizing the printing purpose, the shape and aperture of the nozzle hole of the nozzle 8 are different, which can meet different printing requirements.

[0036] In the embodiment, a partition plate 29 is arranged between the two adjacent nozzles 8, the two ends of each partition plate 29 are fixedly arranged with the inner clamping ring 19 and the outer clamping ring 20, the arrangement of the partition plate 29 increases the stability of the nozzle 8 installation, and also makes the inner clamping ring 19 and the outer clamping ring 20 connected and integrated.

[0037] In the embodiment, the bottom end of the inner cylinder 2 is fixedly arranged with a heating sheet 72, a through hole is arranged in the heating sheet 72 along the vertical direction, the bottom end of the heating sheet 72 is butt-jointed with the corresponding nozzle 8 below, when the material in the inner cylinder 2 is extruded downward, it passes through the through hole in the heating sheet 72 and enters the corresponding nozzle 8 below, and then is extruded downward from the outlet of the nozzle 8, thereby realizing the printing purpose.

[0038] In order to achieve the purpose of automatically installing the nozzle 8 between the inner clamping ring 19 and the outer clamping ring 20, in the embodiment, a nozzle library 30 is fixedly arranged below the transmission disc 18, the nozzle library 30 is uniformly provided with left and right open nozzle compartments 31 in the up and down direction, each nozzle compartment 31 is placed with a nozzle 8, the left side of the nozzle library 30 is provided with a first electric telescopic rod 32, the fixed end of the first electric telescopic rod 32 is provided with a lifting mechanism, the right side of the nozzle library 30 is provided with a mounting platform 33, the lower side of the mounting platform 33 is provided with a second electric telescopic rod 34, when the nozzle 8 needs to be installed, the first electric telescopic rod 32 is extended to the right to push the nozzle 8 in the bottom layer of the nozzle compartment 31 to the right to the upper end surface of the mounting platform 33, and then the second electric telescopic rod 34 pushes the mounting platform 33 upwards, so that the nozzle 8 placed on the mounting platform 33 enters between the corresponding two partitions 29 between the inner clamping ring 19 and the outer clamping ring 20, and the installation of the nozzle 8 is realized, when the nozzle 8 enters between the inner clamping ring 19 and the outer clamping ring 20, the fourth cylinder 26 cooperates with the movement, and finally the plug 27 of the fourth cylinder 26 is inserted into the slot 28 of the nozzle 8, so that the nozzle 8 is fixed, and then the lifting mechanism drives the first electric telescopic rod 32 to move upwards by one nozzle compartment 31, and then the first electric telescopic rod 32 is extended to push the nozzle 8 at the bottom layer to move to the right to the upper end surface of the mounting platform 33, and then the second electric telescopic rod 34 pushes the mounting platform 33 upwards to move, so that the nozzle 8 is installed between the corresponding two partitions 29 between the inner clamping ring 19 and the outer clamping ring 20, and the nozzle 8 is fixed by the fourth cylinder 26, when the nozzle 8 is installed between the inner clamping ring 19 and the outer clamping ring 20, the inner clamping ring 19 and the outer clamping ring 20 are rotated by the transmission shaft 17 to move one position of the nozzle 8, and finally a certain amount of nozzles 8 are installed between the inner clamping ring 19 and the outer clamping ring 20.

[0039] In the embodiment, the lifting mechanism includes a threaded rod 35 arranged in the vertical direction, the threaded rod 35 is threadedly connected with the sliding block 36 fixedly arranged at the fixed end of the first electric telescopic rod 32, the sliding block 36 is slidably arranged on the guide rail 77 in the up and down direction, the threaded rod 35 is rotated to drive the sliding block 36 to move up and down, and then the first electric telescopic rod 32 is driven to move up and down, the output end of the first electric telescopic rod 32 is fixedly provided with a push block 74, and the first electric telescopic rod 32 is extended to push the nozzle 8 at the bottom layer to move to the right to the upper end surface of the mounting platform 33 through the push block 74.

[0040] In the embodiment, the top end of the threaded rod 35 is connected with the transmission shaft 17 through the second electromagnetic clutch 37, the threaded rod 35 rotates or does not rotate as required, the threaded rod 35 is disconnected and connected with the transmission shaft 17 through the second electromagnetic clutch 37, the rotation or non-rotation of the threaded rod 35 is realized, when it is required to install the nozzle 8 between the inner clamping ring 19 and the outer clamping ring 20, the first electric telescopic rod 32 drives the sliding block 36 to move upward by one nozzle warehouse 31 position after driving one nozzle 8, and then drives the first electric telescopic rod 32 to move upward by one nozzle warehouse 31 position; when it is not required to install the nozzle 8 between the inner clamping ring 19 and the outer clamping ring 20, the second electromagnetic clutch 37 is disconnected, the transmission shaft 17 rotates, and the threaded rod 35 remains stationary.

[0041] In order to realize the heating and cooling of the material, in the embodiment, a cooling mechanism is arranged below the printing platform, and a heating mechanism is arranged on the left side of the nozzle warehouse 30, when in use, the cooling mechanism cools and solidifies the material printed above the printing platform, and the heating mechanism preheats and dries the nozzles 8 in the nozzle warehouse 30 and the nozzles 8 in the inner clamping ring 19 and the outer clamping ring 20.

[0042] In the embodiment, the cooling mechanism and the heating mechanism both include heat exchange devices 38, the working medium of the heat exchange devices 38 is nitrogen, the cooling medium of the heat exchange device 38 of the cooling mechanism is cooling liquid, and the heating medium of the heat exchange device 38 of the heating mechanism is water, the water and the cooling liquid are heated and cooled by the hot and cold temperature ends of the Stirling piston 40 system respectively, so that the water obtains heat and returns to the heat exchange device 38 of the heating mechanism to heat the nitrogen, and then preheats and dries the nozzles 8 in the nozzle warehouse 30 and the nozzles 8 in the inner clamping ring 19 and the outer clamping ring 20, the water and the cooling liquid are heated and cooled by the hot and cold temperature ends of the Stirling piston 40 system respectively, so that the temperature of the cooling liquid is reduced and returns to the heat exchange device 38 of the cooling mechanism to cool the nitrogen, and then cools and solidifies the material printed above the printing platform; the nitrogen is communicated with the nitrogen inlet and the nitrogen outlet of the heat exchange devices 38 of the cooling mechanism and the heating mechanism through the nitrogen pipeline 75; a sealed space is formed around the nozzle warehouse 30 and the installation platform 33, the nitrogen enters the sealed space to preheat the nozzles 8 in the nozzle warehouse 30, and at the same time preheat the nozzles 8 between the inner clamping ring 19 and the outer clamping ring 20.

[0043] In the embodiment, the Stirling piston system comprises a cylinder 39 and a piston 40 slidingly arranged in the cylinder 39 in the left-right direction, a piston rod 41 fixedly arranged on the left side of the piston 40, a hot temperature end chamber in the cylinder 39 on the left side of the piston 40, and a cold temperature end chamber in the cylinder 39 on the right side of the piston 40; a communication pipe 42 is arranged between the hot temperature end chamber and the cold temperature end chamber to communicate the hot temperature end chamber and the cold temperature end chamber, two heat exchangers 43 are installed on the communication pipe 42, a regenerator 44 is arranged between the two heat exchangers 43, a first heating medium outlet end 45 of the left heat exchanger 43 and a heating medium inlet end 46 of the heat exchange device 38 of the heating mechanism are communicated through a first hot water pipe 47, a heating medium return end 48 of the left heat exchanger 43 and a second heating medium outlet end 49 of the heat exchange device 38 of the heating mechanism are communicated through a second hot water pipe 50, a cooling medium first outlet end 51 of the right heat exchanger 43 and a cooling medium inlet end 52 of the heat exchange device 38 of the cooling mechanism are communicated through a first cold water pipe 53, a cooling medium return end 54 of the right heat exchanger 43 and a cooling medium second outlet end 55 of the heat exchange device 38 of the cooling mechanism are communicated through a second cold water pipe 56; during operation, the piston 40 is driven to continuously reciprocate, the piston 40 moves to the left to compress a spring 57 sleeved on the piston rod 41, the gas in the cold temperature end chamber expands and the temperature decreases, the gas in the hot temperature end chamber is compressed to generate heat, the gas in the hot temperature end chamber exchanges heat with water through the hot temperature end heat exchanger 43, and reaches the cold temperature end chamber through the regenerator 44 and the cold temperature end heat exchanger 43, the regenerator 44 stores heat through a porous medium (metal mesh). The cooling liquid temperature is slightly increased through heat exchange of the cold temperature end heat exchanger 43. The piston 40 moves to the right, the gas in the cold temperature end chamber is compressed and the temperature increases, but the gas expansion generates more refrigeration capacity than the compression generates heating capacity due to the volume difference, so the gas temperature generally decreases. The cold chamber gas exchanges heat with the cooling liquid through the cold temperature end heat exchanger 43 (i.e. the right heat exchanger 43), and reaches the hot temperature end chamber through the regenerator 44 and the hot temperature end heat exchanger 43 (i.e. the left heat exchanger 43) to complete the whole cycle, and the reciprocating movement of the piston 40 achieves the purposes of refrigeration and heating.

[0044] In the embodiment, the left end of the piston rod 41 is rotationally connected with a connecting rod 58, the left end of the connecting rod 58 is rotationally connected with a crank pin 59, the two ends of the crank pin 59 are both fixedly provided with horizontal cranks in the radial direction, the upper and lower ends of the crank away from the crank pin 59 are both fixedly provided with main rotating shafts 60, the two main rotating shafts 60 are both rotationally connected with a fixed frame 61, the upper main rotating shaft 60 is connected with the output shaft 62 of the second motor through a transmission mechanism; in use, the second motor drives the upper main rotating shaft 60 to rotate through the transmission mechanism, the upper main rotating shaft 60 drives the connecting rod 58 to move through the crank pin 59, the connecting rod 58 drives the piston 40 to reciprocate in the cylinder 39 through the piston rod 41, so as to achieve the purpose of driving the piston 40 to reciprocate.

[0045] In the embodiment, the crank is provided with fourth electric telescopic rods 63; the synchronous extension and contraction of the two fourth electric telescopic rods 63 63 can change the horizontal position of the crank pin 59, so as to change the rotating radius of the crank pin 59, and then change the reciprocating stroke of the piston 40 through the connecting rod 58 and the piston rod 41, so as to achieve the purpose of adjusting the refrigeration and heating capacity of the piston 40 to adjust the temperature.

[0046] In the embodiment, a gas storage tank 71 is arranged between the nitrogen circulation system of the heating mechanism and the nitrogen circulation system of the cooling mechanism, and an electromagnetic valve is arranged at the position where the top end and the bottom end of the gas storage tank 71 are communicated with the nitrogen pipeline, the gas storage tank 71 is used to store nitrogen, and is used to balance the temperature when needed; for example, after the cooling temperature reaches the requirement, the cold nitrogen can be stored in the gas storage tank 71 for standby, when the cooling temperature rises, the cold nitrogen can be released by opening the electromagnetic valve, and the hot nitrogen can also be stored in the gas storage tank 71.

[0047] In order to achieve the purpose of driving the transmission shaft 17 to rotate, in the embodiment, the lower main rotating shaft 60 is connected with the transmission shaft 17 through a speed reducer 73; when the second motor starts, the piston 40 reciprocates, and the transmission shaft 17 also rotates through the lower main rotating shaft 60 and the speed reducer 73, because the second motor continuously operates in use, and the nozzle switching mechanism 6 operates according to the need, in order to solve this problem, the output shaft 64 of the speed reducer and the transmission shaft 17 are connected through a third electromagnetic clutch 65, the third electromagnetic clutch 65 is disconnected in normal printing, and when the nozzle 8 needs to be replaced, the third electromagnetic clutch 65 is closed, so that the speed reducer 73 drives the transmission shaft 17 to rotate, so as to achieve the purpose that the transmission shaft 17 drives the inner clamping ring 19 and the outer clamping ring 20 through the transmission disc 18, and then drives the standby nozzle 8 to rotate through the inner clamping ring 19 and the outer clamping ring 20, so as to achieve the purpose of switching the nozzle 8.

[0048] In order to realize the purpose of forward and reverse rotation switching of the nozzle switching mechanism 6, in the embodiment, the output shaft 64 of the speed reducer above the third electromagnetic clutch 65 and the transmission shaft 17 below the third electromagnetic clutch 65 are both fixedly provided with first bevel gears 67, the two first bevel gears 67 are fixedly provided with a third electric telescopic rod 66 in the side direction, the output shaft of the third electric telescopic rod 66 is fixedly provided with a second bevel gear 68, when the output shaft of the third electric telescopic rod 66 is extended, the second bevel gear 68 is driven to move, so that the second bevel gear 68 is engaged with the two first bevel gears 67; in use, the output shaft 64 of the speed reducer drives the transmission shaft 17 below through the third electromagnetic clutch 65 to rotate, when it is needed to change the rotation direction of the transmission shaft 17, the output shaft of the third electric telescopic rod 66 is extended to drive the second bevel gear 12 to move, so that the second bevel gear 68 is engaged with the two first bevel gears 67, then the third electromagnetic clutch 65 is disconnected, the output shaft 64 of the speed reducer drives the second bevel gear 68 to rotate through the first bevel gear 67 above, and then drives the first bevel gear 67 below to rotate, and then drives the transmission shaft 17 to rotate, so as to realize the purpose of reverse rotation of the transmission shaft 17.

[0049] In the embodiment, the outlet of the nozzle 8 includes five-star, cross, one-word and circular shapes and the like, so as to meet different needs of printing.

[0050] In the embodiment, the printing platform includes a rotary platform 69 connected in rotation, and the upper end surface of the rotary platform 69 is slidably provided with a displacement platform 70 in the radial direction, in use, with the material in the inner cylinder 2 being extruded by the main screw rod 4, the rotation of the rotary platform 69 and the radial movement of the displacement platform 70 are matched with the material extruded in the inner cylinder 2, so that the material forms a printing product on the displacement platform 70, the rotation of the rotary platform 69 and the movement of the displacement platform 70 are realized by corresponding motors through PLC program control, and printing is carried out through the pre-input program and the material extruded in the inner cylinder 2; the structure and movement principle of the rotary platform 69 and the displacement platform 70 are prior art, and will not be described here.

[0051] In the embodiment, the circulation of the heating medium in the first hot water pipe 47 and the second hot water pipe 50 relies on the power provided by a circulating water pump, which is not shown in the figure, and a circulating gas pump is arranged in the nitrogen gas system of the heat exchange device 38, the circulating gas pump delivers nitrogen gas from the nitrogen gas inlet of the heat exchange device 38 into the heat exchange device 38 and then discharges it from the nitrogen gas outlet of the heat exchange device 38, the nitrogen gas heated by the heating mechanism enters the nozzle bank 30 to preheat the nozzles 8 in the nozzle bank 30, and at the same time, enters between the inner clamping ring 19 and the outer clamping ring 20 to preheat the nozzles 8 therebetween; the nitrogen gas cooled by the cooling mechanism enters below the printing platform to cool and solidify the products printed and formed above the displacement platform 70.

[0052] The method for using the stirling type multi-material food 3D printing system:

[0053] A: the first electromagnetic clutch 15 is disconnected, and then the switching gear 14 is pushed upward by the corresponding first cylinder 13 to make the main shaft 10 and the corresponding driven shaft 11 mesh through the gear 12, and then the first electromagnetic clutch 15 is connected, so that the first motor drives the corresponding driven shaft 11 to rotate through the main shaft 10, and then the corresponding extrusion screw 5 is driven to rotate, so that the material in the set extrusion barrel 3 enters the inner barrel 2, and the main screw 4 in the inner barrel 2 further extrudes the material through the nozzle 8 to complete the printing of the food on the printing platform;

[0054] B: the second motor drives the stirling piston system to operate, and the reducer 73 operates at the same time, the stirling piston 40 system exchanges heat with the working medium nitrogen in the heat exchange device 38 through the cold temperature end heat exchanger 43 and the hot temperature end heat exchanger 43 respectively, so that the nitrogen in the heat exchange device 38 of the heating mechanism obtains heat, and the nitrogen in the heat exchange device 38 of the cooling mechanism is cooled, and then the hot nitrogen preheats the nozzle 8 in the nozzle library 30 and the nozzle 8 between the inner clamping ring 19 and the outer clamping ring 20, and the cold nitrogen cools and fixes the material printed on the printing platform;

[0055] C: when the nozzle 8 needs to be replaced, the third electromagnetic clutch 65 is closed or the third electromagnetic clutch 65 is disconnected, the third electric telescopic rod 66 pushes the second bevel gear 68 to move and mesh with the two first bevel gears 67; so that the output shaft 64 of the reducer drives the transmission shaft 17 to rotate, the transmission shaft 17 drives the inner clamping ring 19 and the outer clamping ring 20 to rotate, and then drives the nozzle 8 between the inner clamping ring 19 and the outer clamping ring 20 to rotate, so that the nozzle 8 to be replaced is rotated to the upper side of the inner barrel 2 and is connected with the inner barrel 2, and the nozzle 8 is replaced;

[0056] D: When the nozzles 8 are installed between the inner clamping ring 19 and the outer clamping ring 20 according to the needs, the second electromagnetic clutch 37 is closed, so that the transmission shaft 17 drives the threaded rod 35 to rotate, the threaded rod 35 drives the first electric telescopic rod 32 to move upwards through the sliding block 36, so that the first electric telescopic rod 32 moves to the set position, the second electromagnetic clutch 37 is disconnected, and the first electric telescopic rod 32 extends to the right to push the nozzle 8 in the corresponding nozzle compartment 31 to the mounting platform 33 on the right. At this time, the inner clamping ring 19 and the outer clamping ring 20 are rotated to the set position by the method of step C, so that the positions of the inner clamping ring 19 and the outer clamping ring 20 with empty space are located directly above the mounting platform 33, and then the second electric telescopic rod 34 pushes the mounting platform 33 upwards, so that the mounting platform 33 drives the nozzle 8 to move upwards, so that the nozzle 8 enters between the inner clamping ring 19 and the outer clamping ring 20 and is fixed through the insertion block 27 of the fourth cylinder 26 into the insertion slot 28 of the nozzle 8.

Claims

1. A stirling type multi-material food 3D printing system characterized by: The utility model relates to a kind of 3D printing machine, including the outer tube (1) fixedly arranged along vertical direction, the inner tube (2) is coaxially arranged in the outer tube (1) along the axial direction, several extrusion barrels (3) are evenly arranged along the axial direction between the outer tube (1) and the inner tube (2), the bottom end of extrusion barrel (3) is communicated with the inner tube (2);Main screw (4) and extrusion screw (5) are respectively arranged in the inner tube (2) and extrusion barrel (3) along the axial direction, the main screw (4) is rotatably connected with the inner tube (2), the extrusion screw (5) is rotatably connected with the extrusion barrel (3), the bottom end of outer tube (1) is provided with nozzle switching mechanism (6), the lower side of nozzle switching mechanism (6) is provided with printing platform, the top end of outer tube (1) is provided with screw control mechanism (7), and screw control mechanism (7) is used to control the rotation of corresponding extrusion screw (5);The nozzle switching mechanism (6) includes transmission shaft (17), transmission disc (18), inner clamping ring (19) and outer clamping ring (20), second cylinder (21) is arranged between transmission shaft (17) and transmission disc (18), the output shaft of second cylinder (21) is fixedly provided with top block (22), and the connection between transmission shaft (17) and transmission disc (18) is realized by the second cylinder (21) to top block (22) into the clamping groove of transmission shaft (17) outer surface, transmission disc (18) and inner clamping ring (19) are peripherally provided with a plurality of third cylinders (23), the fixed end of third cylinder (23) is fixedly arranged with transmission disc (18), and the output end of third cylinder (23) is fixedly arranged with the block (24) inserted into the bird groove of the outer surface of inner clamping ring (19), to realize the connection between transmission disc (18) and inner clamping ring (19), the annular slide groove (25) is opened in inner clamping ring (19) and outer clamping ring (20), and inner clamping ring (19) and outer clamping ring (20) are peripherally provided with a plurality of fourth cylinders (26) by annular slide groove (25), the output end of fourth cylinder (26) is close to the annular space formed between inner clamping ring (19) and outer clamping ring (20), the output end of fourth cylinder (26) is fixedly provided with plug block (27), the annular space formed between inner clamping ring (19) and outer clamping ring (20) is peripherally evenly provided with a plurality of nozzles (8), the outer surface of each nozzle (8) is provided with insertion slot (28), the output end of fourth cylinder (26) pushes plug block (27) and inserts into the insertion slot (28) of the outer surface of nozzle (8), to realize the fixed connection of inner clamping ring (19), outer clamping ring (20) and nozzle (8).

2. The Stirling-type multi-material food 3D printing system according to claim 1, characterized in that: The screw control mechanism (7) comprises a main shaft (10) connected with the output shaft (9) of the first motor and a plurality of driven shafts (11) arranged axially around the main shaft (10), the main shaft (10) and the driven shaft (11) are fixedly provided with gears (12) in the same horizontal plane, a first cylinder (13) corresponding to the driven shaft (11) is fixedly arranged in the annular space between the main shaft (10) and the driven shaft (11), and the output shaft of the first cylinder (13) is fixedly provided with a switching gear (14); the bottom end of the main shaft (10) is fixedly arranged with the main screw (4), and the bottom end of the driven shaft (11) is fixedly arranged with the corresponding extrusion screw (5); the first electromagnetic clutch (15) is arranged between the main shaft (10) and the output shaft (9) of the first motor.

3. The Stirling-type multi-material food 3D printing system according to claim 2, characterized in that: A nozzle bank (30) is fixedly arranged below the transmission disc (18), the nozzle bank (30) is uniformly provided with left and right open nozzle compartments (31) in the up-down direction, each nozzle compartment (31) is placed with a nozzle (8), the left side of the nozzle bank (30) is provided with a first electric telescopic rod (32), the fixed end of the first electric telescopic rod (32) is provided with a lifting mechanism, and the right side of the nozzle bank (30) is provided with a mounting platform (33), and the lower side of the mounting platform (33) is provided with a second electric telescopic rod (34).

4. The Stirling-type multi-material food 3D printing system according to claim 3, characterized in that: The lifting mechanism comprises a threaded rod (35) arranged in the vertical direction, the threaded rod (35) is threadedly connected with a sliding block (36) fixedly arranged at the fixed end of the first electric telescopic rod (32), the sliding block (36) is slidingly arranged in the up-down direction, and the output end of the first electric telescopic rod (32) is fixedly provided with a push block (74); the top end of the threaded rod (35) is connected with the transmission shaft (17) through the second electromagnetic clutch (37).

5. The Stirling-type multi-material food 3D printing system according to claim 4, characterized in that: The lower side of the printing platform is provided with a cooling mechanism, and the left side of the nozzle bank (30) is provided with a heating mechanism; the cooling mechanism and the heating mechanism both comprise a heat exchange device (38), the working medium of the heat exchange device (38) is nitrogen, the cooling medium of the heat exchange device (38) of the cooling mechanism is cooling liquid, the heating medium of the heat exchange device (38) of the heating mechanism is water, the water and the cooling liquid are heated and cooled through the hot end and the cold end of the Stirling piston (40) system respectively, so that the water obtains heat and returns to the heat exchange device (38) of the heating mechanism to heat the nitrogen, and then the nozzles (8) in the nozzle bank (30) and the nozzles (8) in the inner clamping ring (19) and the outer clamping ring (20) are preheated and dried, the water and the cooling liquid are heated and cooled through the hot end and the cold end of the Stirling piston (40) system respectively, so that the temperature of the cooling liquid is reduced and returned to the heat exchange device (38) of the cooling mechanism to cool the nitrogen, and then the material printed on the upper side of the printing platform is cooled and solidified.

6. The Stirling-type multi-material food 3D printing system according to claim 5, characterized in that: The stirling piston system comprises a cylinder (39) and a piston (40) slidingly arranged in the cylinder (39) in the left-right direction, a piston rod (41) is fixedly arranged on the left side of the piston (40), a chamber on the left side of the piston (40) in the cylinder (39) is a hot temperature end chamber, a chamber on the right side of the piston (40) in the cylinder (39) is a cold temperature end chamber; a communication pipe (42) is arranged between the hot temperature end chamber and the cold temperature end chamber to communicate the hot temperature end chamber and the cold temperature end chamber, two heat exchangers (43) are installed on the communication pipe (42), a regenerator (44) is arranged between the two heat exchangers (43), a first heating medium outlet end (45) of the left heat exchanger (43) and a heating medium inlet end (46) of the heat exchange device (38) of the heating mechanism are communicated through a first hot water pipe (47), a heating medium return end (48) of the left heat exchanger (43) and a second heating medium outlet end (49) of the heat exchange device (38) of the heating mechanism are communicated through a second hot water pipe (50), a cooling medium first outlet end (51) of the right heat exchanger (43) and a cooling medium inlet end (52) of the heat exchange device (38) of the cooling mechanism are communicated through a first cold water pipe (53), and a cooling medium return end (54) of the right heat exchanger (43) and a cooling medium second outlet end (55) of the heat exchange device (38) of the cooling mechanism are communicated through a second cold water pipe (56).

7. The Stirling-type multi-material food 3D printing system according to claim 6, characterized in that: The left end of the piston rod (41) is rotatably connected with a connecting rod (58), the left end of the connecting rod (58) is rotatably connected with a crank pin (59), the two ends of the crank pin (59) are both fixedly provided with a crank in the radial direction, one end of the crank away from the crank pin (59) is fixedly provided with a main rotating shaft (60), and the two main rotating shafts (60) are rotatably connected with a fixed frame (61). The upper main rotating shaft (60) is connected with the output shaft (62) of the second motor through a transmission mechanism.

8. The Stirling-type multi-material food 3D printing system according to claim 7, characterized in that: The lower main rotating shaft (60) is connected with the transmission shaft (17) through a speed reducer (73).

9. A method of using the printing system of any one of claims 1-8, characterized in that, The method comprises the following steps: A: the first electromagnetic clutch (15) is disconnected, then the corresponding first cylinder (13) pushes the switching gear (14) to move upward, so that the main shaft (10) and the corresponding driven shaft (11) are engaged through the gear (12), then the first electromagnetic clutch (15) is connected, the first motor drives the corresponding driven shaft (11) to rotate through the main shaft (10), and then drives the corresponding extrusion screw (5) to rotate, so that the material in the set extrusion barrel (3) enters the inner barrel (2), and the main screw (4) in the inner barrel (2) extrudes the material through the nozzle (8) to complete the printing of the food on the printing platform; B: The second motor drives the Stirling piston system to run, and the Stirling piston system exchanges heat with the working medium nitrogen in the heat exchange device (38) through the cold temperature end heat exchanger (43) and the hot temperature end heat exchanger (43), so that the nitrogen in the heat exchange device (38) of the heating mechanism obtains heat, and the nitrogen in the heat exchange device (38) of the cooling mechanism is cooled, thereby the hot nitrogen preheats the nozzles (8) in the nozzle bank (30) and the nozzles (8) between the inner clamping ring (19) and the outer clamping ring (20), and the cold nitrogen cools and fixes the printed material above the printing platform; C: When the nozzle (8) needs to be replaced, the transmission shaft (17) drives the inner clamping ring (19) and the outer clamping ring (20) to rotate, thereby driving the nozzle (8) between the inner clamping ring (19) and the outer clamping ring (20) to rotate, so that the nozzle (8) to be replaced is rotated to the upper side of the inner cylinder (2) and is connected with the inner cylinder (2), and the nozzle (8) is replaced; D: When the nozzle (8) needs to be installed between the inner clamping ring (19) and the outer clamping ring (20), the second electromagnetic clutch (37) is closed, so that the transmission shaft (17) drives the threaded rod (35) to rotate, the threaded rod (35) drives the first electric telescopic rod (32) to move upwards through the sliding block (36), so that the first electric telescopic rod (32) moves to the set position, the second electromagnetic clutch (37) is disconnected, and the first electric telescopic rod (32) extends to the right to push the nozzle (8) in the corresponding nozzle chamber (31) to the installation platform (33) on the right side. At this time, the inner clamping ring (19) and the outer clamping ring (20) are rotated to the set position by the method of step C, so that the positions of the inner clamping ring (19) and the outer clamping ring (20) with empty space are located directly above the installation platform (33), and then the second electric telescopic rod (34) pushes the installation platform (33) upwards, so that the installation platform (33) drives the nozzle (8) to move upwards, so that the nozzle (8) enters between the inner clamping ring (19) and the outer clamping ring (20) and is fixed by the insertion block (27) of the fourth cylinder (26) into the insertion slot (28) of the nozzle (8).

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